A cell scheduler for non-real-time traffic with service fairness in ATM networks

Abstract

Non-real-time (NRT) services, including nrt-VBR, ABR and UBR traffic, are intended for data applications. Although NRT services do not have stringent QoS requirements for cell transfer delay and cell delay variation, ATM networks should provide NRT services with excellent performance in other criteria such as cell loss ratio (CLR), buffer size requirement and service fairness. Thus, as much as these criteria as possible should be considered when designing a cell scheduler to deal with NRT services. We present a novel cell scheduling scheme, called buffer minimized and service fairness (BMSF), to schedule NRT services in ATM networks. By using probability constraints and allowing a connection with the longest buffer size to transmit first, BMSF attains satisfactory performance with respect to the maximum buffer size requirement, CLR, and service fairness regarding both maximum buffer size and cell waiting delay criteria. Simulation results demonstrate that BMSF simultaneously performs better than some prominent schemes in terms of these criteria, particularly when NRT have diverse arrival rates.